Method of grooving pipe fittings and the like



c. A. CAMPBELL Filed Jan. 16, 1936' w w W 1 MW a n w m w. w M w m METHODOF GROOV-ING PIPE FITTINGS AND THE LIKE I-Il lllll I 45 out the grooveor Emma S'ept." 21,1937

uNiTao STATES METHOD OF GROOVING PIPE FITTINS Charles A. Campbell,Watertown, N. Y., assignor to The New York Air Brake Company, acorporation of New Jersey Application January 16 1936, Serial No. 59,450

This invention relates to sweatedfjoints, and particularly to sweatedJoints formed between a rod or tube and an encirc'ling sleeve.

It has long been known that if the clearance or interval between the twoelements to be sweated together be of capillary thickness, and if thetwo elements be mixed before assembly and properly heated, molten solderwill enter the capillaryinterval by'capillary attraction and distributeitself throughout the entire capillary interval, that is in the case: ofa. sleeve Joint, throughout the area between the opposed surfaces oftherod or tube on the one hand and the encircling sleeve on the other. InPatent 1,770,852. Hill proposes the use of what he calls an exterioropening leading through the wall of the fitting and preferablycommunicating with a'groove which encircles the capillary zoneintermediate the ends thereof. 20 patent states that the-use of thegroove is 'desirable but is not essential to the formation of asatisfactory Joint.

- Manufacture of fittings with an internal groove and radially drilledports is needlessly expensive, and one purpose of the-present inventionis to simplify the manufacture of fittings for sw'eated joints-and atthe same time improve the character of the Joint produced. The inventionpro-- I vides for cutting the annular internal groove and cuttinga sprueor feed port leading thereto along the joint itself by two successiveoperations performed by a single tool. of novel forms According ,to thepreferred practice the fitting is mounted in a'chuck to turn on itsaxis, and while 35 being rotatedis provided with saw tooth.annulargrooves by the action of a cutter or bit car ried in a boring baror the equivalent, and fed radially outward to the cut. I

While thenumber of grooves is subject to vari- 40 ation,.and the use ofa single groove is within the purview of the invention, satisfactoryresults have been secured by the use of three small grooves, as-shown inthe drawing.

After the tool orbit has been v groovesto the full desired depth,

the rotation of the chuck is; stopped and-the boring toolis'withdr'awnin the direction of the axis of the fitting. At such time thesawetoothed \cutt er or bit acts as a breach and cuts a lono gitudinalgroove connecting the annular grooves with oneend. of the fitting. Inthis way the grooves and a'communicating sprue are formed expeditiouslyand cheaply. 7f J The operation :ca'n be carried out in various 55 typesof machine tools capable of producing'rel- .4 Claims. (01. 29-151) Thefed outward or ative rotation of the fitting with respect to the toolwhile the tool is fed radially, and axial travel of the tool when thefitting is at rest. While the operation can be carried out in anordinary lathe,

simple automatic-machines can readily be developed to carry out theoperations in the desired sequence.

Tests have shown remarkably satisfactory resuits with reference to theJoint produced bythe use of such fittings.

The invention will now be described in connection with the accompanyingdrawing, in which,- 1 I Fig. 1 is a side elevation of a threaded nipplewith sleeve according to the invention.

Fig. 2 is'a section on the line 2--2 of Fig. 1.

' Fig. 3 is a view similar to Fig. 2 but showing the tube inserted. p

Fig. 4 is a view similar to Fig. 3 after capillary flow of solder.

Fig. 5is an axial section of the cutter bar with the bit or cutter inplace.

Fig. 6 is a transverse section on the-lineB-t of Fig. 5, drawn on anenlarged scale. 4

Fig; '7 is aperspective view of the cutter or bit. The invention isapplicable to all types of fittings including T's, elbows, Us, and infact any soldered sleeve Joint between a tube end or rod end and asocketedmember. Hence the embodimerit illustrated is exemplary.

The'iitting II having port or passage I2 is counterbo'red at I3 to formshoulder H. The counterbore i8 is such as to receive the end of anelement l5, shown as a tube, though so far as the invention is concernedit might be a rod. 35 The clearance between the element II and theencircling counterbore is dimensioned to ensure the desired capillaryflow.

Before element l5 isinserted one or more circumferentiaifgrooves ii arecut within the counterborev preferably by rotating the fitting andfeeding the tool (hereinafter described) radially outward. This, broadlyconsidered, is a tumins operation. r .Then rotation is stopped andwithout with-' drawing the tool from the cut the tool iswithdrawn in adirection parallel with the axis of the counterbore' l3, broaching agroove I] which communicates with the groove or grooves l 6. A notch 'llmay be cutat the endof groove l1 but this is 'not essential. Y

The tool used is preferably but not necessarily a removable bit I!mounted and transvesely adiustable in a stock or boring bar 2|. amping55 is effected by a rod 22 axially slidable-in stock 2i and set by athreaded plug 21. v

The bit I! has cutting teeth 24, one for each groove l8, and these arepreferably of the buttressed or saw tooth type and preferably not uhdemut on the faces 25. They are backed off as indicated at 26 (Fig. 6)to afford clearance -behind the cutting edge during turning.

After turning is completed the tool is withdrawn in a direction parallelwith the axis of counterbore l3 and the teeth 24 execute a scraping orbroaching out which forms the groove H.

To solder the joint the counterbore i3 and the end of element ii arefluxed. While the end of element-i5 is-inserted in counterbore l3 andwhile the parts are suitably heated, solderls fed to the outer end ofgroove l1. Even with the parts in the position of Fig. 3 the solder willflow up groove I1 and around grooves l8 and will enter the entirecapillary interval between element l5 and counterbore l3.

The solder is indicated at 21 in Fig. 4. To indicate the extent of thecapillary film of solder, this has been exaggerated in thickness, sincethe mm cannot be illustrated on the true scale of the drawing.

What is claimed is,-

'1.-'I'he method of grooving a cylindrical component to be used informing sweated pipe or rod joints which comprises causing a cutter tocut at least one annular groove around the component, by relativerotation and radial feed betweenthe component and cutter; and then atthe completion of said feed causing relative motion between the cutterand component in the direction of the axis of the component whereby asprue groove communicating with the annular groove is formed.

2. The method of grooving a cylindrical component to be used in formingsweated pipe or rod joints, which comprises forming at least onecircumferential groove and a communicating longitudinal groove by twogrooving operations successively performed by a toothed forming tool,one of said operations being a broaching operation and the other aturning operation in which respectively the paths of the work relativelyto the tool are at approximately to one another.

3. The method of groovinga cylindrical component to be used for sweatedpipe or rod Joints, which comprises turning a circumferential groove insaid component by feeding a toothed forming tool to the cut and thenwithout retracting said forming tool from the groove, traversing theforming tool to broach a groove communicating with the turned groove andadapted to serve as a sprue.

4. The method of grooving a cylindrical component to be used in formingsweated pipe or rod joints, which comprises turning multiple grooves byfeeding to the work a forming cutter

